Prayer as Covenant

“Where does prayer come from? Whether prayer is expressed in words or gestures, it is the whole man who prays. But in naming the source of prayer, Scripture speaks sometimes of the soul or the spirit, but most often of the heart (more than a thousand times). According to Scripture, it is the heart that prays. ... The heart is the dwelling-place where I am, where I live; according to the Semitic or Biblical expression, the heart is the place ‘to which I withdraw.’ The heart is our hidden center, beyond the grasp of our reason and of others; only the Spirit of God can fathom the human heart and know it fully. The heart is the place of decision, deeper than our psychic drives. It is the place of truth, where we choose life or death. It is the place of encounter, because as image of God we live in relation: it is the place of covenant. ... Christian prayer is a covenant relationship between God and man in Christ...”

(From the Catechism of the Catholic Church)